Laminated sheet material



Jan. 31, 1967 P. s. BETToLl 3,300,927

LAMINATED S HEET MATERIAL Filed Jan. 21, 1963 l Phillip STep hen BeTToliBY QW @MMA @@Tww Le ATTORNEYS United States 'Patent f 3,300,927LAMINATEI) SHEET MATERIAL Phillip Stephen Bettoli, Martinsville, NJ.,assigner to The Ruberoid Company, a corporation of New Jersey Filed lan.21, 1963, Ser. No. 252,890 14 Claims. (Cl. 52-309) This inventionrelates to a laminated sheet material for covering and protecting avariety of surfaces, and more particularly relates to apolyvinylfiuori-de laminant with excellent weathering characteristicsfor use in the roofing and siding trades.

It is an object of this invention to provide a material for covering andprotecting the exposed surfaces of a variety of structures. It is afurther object to provide a flexible roofing or siding material whichcan lbe used on surfaces having irregular or unusual contours. Thematerial of this invention, polyvinylfluoride plastic film laminated toAa non-ammable, elastomeric-impregnated asbestos `felt backing, hasexcellent weathering characteristics and will not erode, crack or crazeupon long exposure to visible or ultraviolet radiation or climaticextremes of temperature -or humidity. It has excellent dimensionalstability and substantially permanently remains strong and flexibleunder all climatic conditions. In addition, the pigmented coveringmaterial of this invention provides a decorative and colorful materialhaving durable color and one which is substantially stain-resistant.

It is another object of this invention to provide a rigid structural`material having an outer covering of polyvinylffuoride plastic film,for use in the building trades, which incorporates the advantages of the-laminated sheet material described in the preceding paragraph.

It is a further object of this invention to provide a roof having a roofdeck covered with a laminant material which is less than one-sixth theweight of a conventional built-up roof covering, and which possesses thedesirable characteristics of being non-flammable and of not degradingwith age or upon exposure to climatic extremes of weather. In itspigmented form, the laminant material retains its color and does notrequire periodic painting. Moreover, the mechanical strength andflexibility of the laminant accomodates itself to the expansion orcontraction of the underlying roof deck.

These and other objects implicit in this specification are accomplished,in general, by the advantageous use of a laminant comprising apolyvinylfluoride plastic film adhesively secured to an asbestos feltbacking which has been impregnated' with an elastomeric binder, such aspolychloroprene, neoprene and polyvinylacetate, polychloroprene andacrylonitrile or polychloroprene and other elastomeric additives whichyield a non-flammable product. The polyvinyl-fluoride film is pigmented,yielding a decorative, colored laminant material. The pigmented film issubstantially opaque to incident ultraviolet and visible radiation andprotects the elastomer-impregnated backing and under-structure frompossible ph-otochemical degradation. The laminant may be used alone as aroofing or siding material or it may be combine-d with suitable rigidslabs of insulating material for use generally as a covering materialfor buildings.

In the accompanying drawings, FIGURE l is a crosssectional view of thelaminated material of this invention;

FIGURE 2 is a plan view of a section of a roofing material embodiment ofthis invention;

FIGURE 3 is a plan view of a roof with portions of the roong materialbroken away to show the disposition of the laminated material of thisinvention; and

FIGURE 4 is a cross-sectional view of a rigid structural material ofthis invention.

Polyvinyluoride, having the structural formula tt u L J H H n and in theform of a plastic film of uniform thickness, is the polyvinylfluorideused in the laminant of this invention. It is extremely inert andunreactive, and withstands extremes of temperature and humidity.Moreover, it is not significantly degraded by ultraviolet radiation.Being flexible and readily available in pigmented form, it is suitablefor use with roofs having unusual contour or form, for example,parabolic roofs which cannot readily be covered with conventionalasphaltic materials. It is also suitable for roofs where a particularcolor is desired, without the disadvantages of having to paint the same.It is not practical to use polyvinyllluoride film alone, however. Thethickness of the film, usually l to 4 mils, presents handling andworking problems. Used alone, it cannot be handled with availableroofing tools -according to established techniques. In addition,adhesives available for on-site .application to roofs and the like, areinadequate for producing a satisfactory bond between the inert film andthe surface to which it is applied.

Referring to FIG. l the laminant 10 of this invention comprisespolyvinylliuoride plastic film 11 secured to an asbestos backing 12 bymeans of a therm-osetting elastotmeric adhesive I3. The bond betweenfilm and felt is permanent. The felt backing 12, which .is impregnatedwith an elastomer, preferably neoprene, is also iiexible. Thecombination of film and felt backing obviates the handling difficultiesreferred to above and enables the laminant It) to be applied to surfaceswith the usual asphaltic type adhesives. Moreover, the laminant hasincreased resistance to mechanical damage, punctures and tears, to whichthe unsupported polyvinylfiuoride film would otherwise be particularlysusceptible.

Bitumen-impregnated feits are unsatisfactory as a backing material forpolyvinylfiuoride. They can cause some staining of the .plastic film,|but more importantly, they are or become inflexible, usually embrittleon aging and are inflammable. Elast-omeric-impregnated felt, on theother hand, remains substantially permanently fiexible on exposure toclimatic extremes of temperature and humidity. Pro-per selection of theelastomer will yield a non-fiamtmable laminant. In this regard,polychloroprene (Du Pont neoprene) is the preferred elastomeric binderfor the laminant of this invention. Since polyvinylfluoride plastic filmis also non-flammable, the resultant laminant (with the non-flammablepolychloroprene-impregnated backing) will possess this desirablecharacteristic. Other non-flammable elastomers, including mixtures ofpolychloroprene and polyvinylacetate or polychloroprene and othernon-flammable additives may also be used to impregnate the asbestosfelt. Non-flammable mixtures of polychloroprene and aciylonitrile orother elastomeric binders are also suitable. In any case, theimpregnated product should be non-flammable (by which term is meanteither non-combustible or self-extinguishing) providing a materialhaving an advantage over iniiammable prior art products, such asbitumen-saturated felts.

Asbestos felt is the preferred material for use in the laminant productof this invention. Organic f-elts or papers have been found to lackdimensional stability and fiame resistance. They also embrittle anddegrade with age. Glass fibers are difficult to bond topolyvinylfiuoride and lack desirable elongation characteristics.Aluminum foil does not provide optimum handling characteristics and issusceptible to mechanical damage. Elastomericimpregnated asbestos feltis preferred over ordnary, unsaturated asbestos paper, which is notsuitable as a backing for use in this invention, since unimpregnatedasbestos does not have the tensile strength, the tear resistance and thegeneral toughness of the impregnated form. In addition, theunimpregnated felt is adversely affected by moisture, having poor wetstrength when wetted. The porosity of unsaturated asbestos felt is suchthat the asbestos fibers would absorb excessive quantities ofelastomeric adhesive during the step of laminating7 polyvinylfluoridefilm to the backing.

Thus, the preferred backing of the invention herein ispolychloroprene-impregnated asbestos felt. It is nonflammable, retainsits fiexibility for long periods of time and is resistant to heat aging.It is also suitable for use with conventional mopping asphalts orcold-applied cements. Polychloroprene-impregnated asbestos felt,moreover, is not subject to microbiological degradation and is thereforesuperior to organic-fiber backings. The impregnated asbestos feltcontains from about to about by Weight of polychloroprene.

Other elastomeric compounds may be used to impregnate the asbestos. Asindicated above, however, it is preferred that the final product benon-fiammable. By way of an example, a blend of one part by weight ofpolyvinylacetate with three parts by weight `of polychloroprene is alsosuitable. As in the case of polychloroprene alone, this blend is addedto the asbestos felt in an amount sufiicient to provide a backing havingfrom about 15% to about 25% by weight of the blend. The quantity ofpolyvinylacetate in the blend may be increased to about 35%. Othersuitable elastomeric mixtures include: a copolymer `consisting of 82% byweight of polychloroprene and 18% by weight of acrylonitrile; or a blendof one part by weight of polychl-oroprene to one part by weight ofacrylonitrile. Again, the quantity of these mixtures added to theasbestos should preferably be sufiicient to produce a final productcontaining about 15 to about 25% by weight of elastomer.

Polyvinylfluoride plastic film is clear and transparent to ultravioletand visible radiation. As an increasing amount of pigment is added tothe film, the latter becomes increasingly opaque to both ultravioletradiation and to light in the visible wave length range. Pigment may beadded to the polyvinylfluoride in a quantity up to about 25% by weight,depending upon the color effect and opacity desired. It is notrecommended that an amount of pigment greater than 25% by weight beadded,

celerate the rate at which the photochemical decomposition of thepolychloroprene takes place, leading to early failure of the adhesivebinding of the film to the felt. In the presence of asphalt oils, theshort wave lengths of visible light are particular destructive of thepolychloroprene. Accordingly, the film should be sufiiciently opaque toultraviolet and visible light, and particularly to visible light of theshorter wave lengths, to substantially completely obscure the passage ofsuch light to the underlying polychloroprene-impregnated felt.

A 2-mil white film, pigmented with titanium dioxide (15% by Weight) willtransmit about 10% of near-ultraviolet incident radiation. If theconcentration of the pigment is raised to 25% by weight, 8.4% istransmitted. The addition of 1/2% carbon black to the latter filmpigmentation reduces light transmission to 4.5% of the incidentradiations. With the addition of sufficient carbon black to make thefilm gray, it will transmit less than 0.2% of incident radiation. (Thesefigures all apply to transmission through the film of radiation of 5461A.) Accordingly, the presence of at least a small amount of carbon blackin the film pigments is desirable to prevent degradation of the adhesive`bond of the film to a polychloroprene-impregnated felt in consequenceof exposure to sunlight.

Another means that may be adopted to protect the bond of the film to apolychloroprene-impregnated felt is to pigment the adhesive which bindsthe film to the felt, thereby to reduce its light-transmissioncharacteristics. Transmission of light through the adhesive may besubstantially nullified by the incorporation therein of carbon black.Thus, a 2-mil film, containing 25% by weight of TiOZ and with 1% byweight of carbon black in the adhesive will transmit only about 3.3% ofincident radiation of 5461 A., which is in the range of destructive wavelengths. With 8% to 10% carbon in the adhesive, transmission of lightthrough it is substantially precluded.

The effect of light transmission on bond strength is illustrated in thefollowing table. In the table, results are given of tests on bindstrength of film to felt after accelerated radiation exposure oflaminants of various films bonded to polychloroprene-impregnatedasbestos felt with 0.3 mil of clear adhesive (except for the laminatesspecified on the last line, in which case the adhesive was pigmented)the laminates in all cases were adhered to a supporting panel by anasphalt.

TABLE 1.-EFFECTS OF RADIATION ON BOND STRENGTH [All bonds measured atand given in grams/inch] Accelerated Radiation Percent Exposure HoursLaminate transmission Initial at 5,461 A. Bond 2-milwl1ite (15% TiOz) l080 2-mil white (25% TiO2) 8.4 240 1.5-mil beige 4. 7 350 2.0-mil grey 0.18 1, 150 2-xnil white (with 4% carbon in adhesive) 0.2 1, 550

however, as this will adversely affect the durability of the film.

Opacity of the covering film is considerably important. It has beenfound that if there is any substantial penetration of visible orultraviolet light through the film, the bond of the film to thepolychloroprene-impregnated felt deteriorates slowly, and ultimatelywill fail. Careful studies have shown that visible radiation in thenear-ultraviolet portion of the spectrum causes a slow degradation ofthe polychloroprene, with the result that the adhesive bond to the feltfails over a period of time. When an asphaltic cement is used to adherethe felt to a roof deck or wall surface, asphalt oils which tend tomigrate through the felt to the interface of felt and adhesive greatlyac- 75 in thicknesses.

The presence of carbon in the adhesive maintains bond strength at a highlevel for long periods of time. The increase in bond strength upon agingshown in one instance in Table l is due to post-curing. Translated intoterms of service life of a roof deck covered with the laminant materialof this invention, a laminant having a 2 mil white film (25 TiO2) has aprojected exterior life of at least 20 years. A laminant employing a 2mil white film with carbon black in the adhesive has a projectedexterior life in excess of 30 years, which is considerably greater thanthat of the usual roofing materials heretofore available.

It should be noted that the covering film may be varied The minimumacceptable thickness is about 1 mil. Four mils thickness isapproximately the upper limit, taking factors of economy and filmmanufacturing specifications into consideration. Should the laminant beapplied to area subject to heavy traic, a 4 mil layer ofpolyvinylfluoride film would be preferable.

Curing-type elastomeric adhesives are suitable for laminatingpolyvinylfiuoride securely to the saturated asbestos felt backing. Anacrylonitrile adhesive with phenolic tackiiers and an isocyanate curingagent is perhaps most suitable and may be regarded as yielding optimumresults. In general, any elastomeric adhesive may be used which retainsits flexibility and will not undergo resinification upon long exposureto light or climatic extremes. Polysulde adhesives, although expensiveand ditiicult to handle, are also suitable.

Elastomeric saturated asbestos 12 is manufactured according toestablished techniques with the components and in the quantities statedabove. The following examples are included for purposes of illustration,it being understood that other ingredients are also useful to providethe laminant material of this invention.

Example 1 Polychloroprene was slurried in a paper makers beater at about60-70 F., along with a dispersing agent, an anti-oxidant, Zinc oxide andalum, the latter having been added to precipitate the polychloroprene.The polychloroprene was added in the form of a solids latex (Du PontNeoprene Latex #735.) Additions of alum were made at the beater head boxto control foam and to maintain an acid pH. Polychloroprene latex wasadded in sufficient quantity to provide a finished product containing20% polychloroprene solids. Lamination of the polyvinylfluoride plasticfilm 11 to the polychloroprene saturated felt backing 12 wasaccomplished with a nitrilephenolic adhesive (Du Pont Modified SyntheticRubber Adhesive type 4684, containing 10% DuPont Curing Agent RC 805),to which 4% by weight of aqueous carbon black had been added. Thelaminating adhesive was adjusted to a viscosity of 16 to 18 (Zahn cupNo. 3) with methyl ethyl ketone, and the coating roll employed for thelamination operation Was adjusted to apply the equivalent of 0.5 mil ofdry adhesive solids. The adhesive was applied directly to apolyvinyluoride film of 2 mils thickness, the film then being passedthrough a drying tower to remove a portion of the methyl ethyl ketone.The film 11 was laminated to the smooth side of thepolychloroprene-impregnated felt backing 12 by a conventional nip rolllaminating operation. The nip roll was maintained at 200 F. and 120p.s.i. Machine speed was about 150 feet per minute. (At speeds below 150feet per minute, the temperature should be reduced to 150 F.) Thelaminated product 10 was then subjected to additional heat and to a highvelocity air stream to remove the remainder of the laminating solventfrom the finished product.

Example 2 A slurry of asbestos was made in a beater under the conditionsand with the ingredients described in Example 1, except that in place ofpolychloroprene, a mixture of polychloroprene and polyvinylacetate inthe weight ratio of 3:1 was charged to the beater. The amount introducedwas suicient to produce a product having 18% by weight of theelastomeric mixture. Lamination was carried out in the manner describedin Example 1. A 2% by weight addition of carbon black was made to theadhesive prior to lamination and the coating roll was adjusted to applythe equivalent of 0.35 mil dry adhesive solids. The resulting productwas non-flammable, flexibl and otherwise suited to the variety of usesto which the laminant of this invention may be put.

The laminant material produced in either of the ways Y described above,or in other ways may be further processed for use as a flexible rootingor siding material; or

it may be laminated, in turn, to a suitable, rigid insulating substancefor use as a covering material where rigidity is a desiredcharacteristic, as in sidings for buildings.

In the production of flexible roofing material 14 the lm and felt arepreferably trimmed and cut in predetermined widths. The nal product thusobtained is shown in FIG. 2. Film 11 is applied to the felt 12 in amanner such that, in the final product, the longitudinal edge of the lm15 defines a selvedge 16 of a uniform width. Selvedge 16 permitsoverlapping of successive lengths of roofing material as described belw.It also allows for the bonding of asbestos felt on asbestos felt, andnot felt on polyvinyluoride. Hence, a wide variety of adhesives,including bitumen cements may be used. Rooing material of a standardwidth may also be produced without providing a film-free selvedge 16,should this be desired.

Referring now to FIG. 3, application of the roofing material shown inFIG. 2 will be described. FIG. 3 depicts a standard wood roof deck 17which is mopped with roofing asphalt 18 (12 lbs/100 sq. ft.). It shouldbe understood that the rooting material of this invention may be appliedto a variety of roof decks, including decks of wood, concrete andinsulation. It may also be applied by a variety of means, includingeither hot asphalt or cold cement applications. Conventional coated,sanded and asphalt-saturated base sheet 19-22 is applied to deck 17which has been asphalt mopped. The base sheet is applied in successivelengths 19, 20, 21 and 22, with one length (21 for example) overlappingthe preceding su'bjacent length (Z0) by about 4 inches. The base sheetis nailed according to established techniques.

Roofing material 14, having a selvedge 16, as shown in FIG. 2, isapplied in a manner similar to base sheet 19; viz., 'by mopping andapplying overlapping lengths of rooting material 14. Thus, the area tobe occupied by a length 23 -of rooting material 14 is mopped withrooting asphalt 24 (20 lbs./ 100 sq. ft.) and a length 23 is laid. Anarea -adjacent the length 23 is also mopped with asphalt. The selvedge16 of length 23 is also mopped to within one inch of the longitudinaledge 1S of the polyvinyluoride lm 11. A next ilength 25 of rootingmaterial 14 is then laid with an edge 26 thereof completely covering theselvedge 16 of the first length 23 and superadjacent the same.Successive lengths are applied in the same fashion, care being takenthat the selvedge 16 of each length is mopped only to a maximum of oneinch -away from the longitudinal edge 15. This will insure that asphalt24 does not ooze out onto the exposed surface -of the material 14. Theend result of overlapping successive lengths of roong material 14 isshown in FIGURE 3 4as lengths 27 `and 23. The operation may be`completed by sealing the seams between overlapping lengths (i.e., endlaps 29 and side laps 30) with a pressure-sensitive tape, preferably asimilarly pigmented polyvinylfluoride plastic film. The seams may alsobe closed with a silicone caulking compound or suitable polysulfiderubber cements.

A roof to which a preferred pigmented white film rooting material 14 hasbeen applied has a reliectivity upwards of 75% and is completelywaterproof and vaporproof.

Variations of the above methods may be employed in order to adopt theproduct of this invention to various environments or to use the productwith other mopping materials, such as a cold method cement. For example,a pre-cast concrete roof deck may be coated with the roofing material14, by simply priming with a suitable concrete primer and then applyingthe rooting material 14 directly thereto with conventional rroongbitumens. Should it be desirable, a roofing materia-l Without theselvedge may also be employed. In this vease, lengths of material 14 areno-t overlapped and the longitudinal edges of the successive Ilengths ofmaterial merely abut each other. The seams are then sealed withpolyvinyluoride 7 plastic tape, silicone caulking compound orpolysulfide rubber cement.

Referring to FIG. 4, a product for use in covering and protectingstructures may be made by securing the laminant 10 of this invention toa rigid slab of insulating material 31 with a suitable adhesive 32, suchas asphalt or the like. The laminant -comprises a layer ofpolyvinylfluoride plastic film 11 adhesively secured (by means ofadhesive 13) to elastomer-impregnated asbestos 12. The felt backing 12is secured to the insulating material, producing a structural ma-terialwherein the polyvinylfiuoride film 11 is t-he exposed surface. The rigidslab 31 may be manufactured from a variety of conventional insulatingmaterials which have been Ifound to .be useful in the building trades,such as wood, including shredded wood, wood shavings, excelsior, orpaper, newspaper, vermiculite, gravel, stones, cement or cement withlight aggregates.

I claim:

1. A material for covering and protecting the exposed surfaces tostructures comprising a substantially opaque polyvinylfiuoride plasticfilm of l`low light transmissability having a uniform thickness of atleast about one mil and an asbestos felt backing impregnated withpolychloroprene, said polyvinylfluoride plastic film having uniformlyincorporated therein up to 25 by weight of an opacifying pigment, saidfilm adhesively secured to said backing by means of an elastomeric.adhesive of low light transmissability containing up to 10% by weight ofopacifying pigment.

2. A weather and fire resistant roofing material comprising apolyvinylfiuoride plastic film adhesively laminated to an asbestos feltbacking by means of a thermosetting elastomeric adhesive, said asbestosfelt .backing impregnated with a non-fiammable elastomeric binder, andsaid plastic film being substantially opaque to protect the adhesivebond thereof to the backing from photochemieal degradation.

3. A flexible roofing material comprising an asbestos felt backingimpregnated with from about 15% to about 25% of polychloroprene and apolyvinylfiuoride plastic film having a uniform thickness of at leastabout one mil secured to said asbestos felt 'backing by means of athermosetting elastomeric adhesive, said lm 'having uniformlyincorporated therein up to 25% by weight of pigments comprising carbonblack and 4being substantially opaque.

4. The roofing material of claim 3 wherein the elastomeric adhesivecontains up to 10% by weight of carbon black.

5. The roofing material of claim 3 wherein the asbestos felt backing isimpregnated with from about 15 to about 25% by weight ofpolychloroprene.

6. A Weather and fire resistant fiexible roofing material comprising anasbestos felt backing impregnated with from about 15% to about 25% byweight of a mixture containing one part by weigh-t of polychloropreneand up to one part by weight of acrylonitrile, and a pigmentedsubstantially opaque polyvinylfiuoride plastic film having a uniformthickness of at least about one mil secured to said asbestos feltbacking by means of a thermosetting elastomeric adhesive.

7. A weather and fire resistant flexible roofing material comprising anasbestos felt backing impregnated with from about 15% to about 25% lbyweight of a mixture c-on-taining polychloroprene and polyvinylacetate inthe weight ratio of about 3 to l, and a pigmented substantially opaquepolyvinylfiuoride plastic film having a uni- Iform thickness of at leastabout one mil secured to said asbestos felt backing by means of athermosetting elastomeric adhesive.

8. A roof comprising a roof deck and fiexible roofing polyvinylfluorideplastic film having a uniform thickness of at least .about one mil, andan asbestos felt backing impregnated with from about 15% to about 25% byweight of polychloroprene, said film secured to said asbestos feltbacking by means of a thermosetting elastomeric adhesive.

9. A roof in accordance with claim 8 wherein the width of saidpolyvinylfiuoride plastic film is less than the width of said backingsuch that a film-free edge of uniform width is defined by thelongitudinal edge of said film, said roofing material being disposed onsaid roof deck in overlapping fashion such that a superadjacent lengthof said roofing material covers the said film-free edge of a subjacentlength of said roofing material, and wherein the seams between saidlength of roofing materials are sealed with pressure-sensitive adhesivetape, said tape comprising polyvinylfluoride plastic film.

10. A roof comprising a roof deck and successive lengths of flexibleroofing material having a uniform width, said material covering saidroof deck, said roofing material being weather and fire resistant anduniformly secured to said roof deck with an asphaltic adhesive, saidroofing material comprising a pigmented substantially opaquepolyvinylfiuoride plastic film having a uniform thickness of at lea-stabout one mil, and an asbestos felt backing impregnated with from about15% to about 25% by weight of polychloroprene, said film secured to saidIasbestos felt backing by means of a thermosetting elastomeric adhesivecontaining up to 10% lby weight of carbon black.

11. A roof comprising a roof deck and successive lengths of flexibleroofing material having a uniform width, said material covering saidroof deck, said roofing material being weather and tire resistant anduniformly secured to said roof deck with an asphaltic adhesive, saidroofing material comprising a pigmented substantially opaquepolyvinylfiuoride plastic film having a uniform thickness of -at leastone mil, and an asbestos felt backing impregnated with from about 15% toabout '25% by weight of polychloroprene, said film secured to saidasbestos felt backing by means of a thermosetting, elastomeric adhesive,said roofing material disposed on said roof deck in a manner such that allongitudinal edge of one of said lengths of roofing material abuts thelongitudinal edge of another of said lengths adjacent to it, the seamdefined by said abutting longitudinal edges being sealed bypressure-sensitive adhesive tape, said tape comprising polyvinylfluorideplastic film.

12. A structure for covering surfaces comprising a rigid slab of aninsulating material selected from the group consisting of wood, shreddedWood, wood shavings, excelsior, paper, vermiculite, gravel, cement andcement with light aggregates incorporated therein, said slab coveredwith a Weather and fire resistant sheet material comprising an asbestosfelt backing adhesively secured to said slab, said asbestos felt`backing impregnated with from about 15 to about 25% by weight ofpolychloroprene, and a pigmented substantially opaque polyvinylfluorideplastic film having a uniform thickness of at least one mil, said filmsecured to said backing with a thermosetting elastomeric adhesivecontaining up to 10% by weight of carbon black.

13. A Weather and fire resistant material for covering and protectingthe exposed surfaces of structures comprising a laminate ofpolyvinylffuoride plastic film secured by an elastomeric adhesive to anyasbestos felt backing irnpreganted with a non-flammable elastomericbinder, said plastic film being substantially opaque to protect theadhesive bond thereof to the backing from photochemical degradation.

14. A structure for covering surfaces comprising a rigid slab ofinsulating material covered with a weather and fire resistant sheetmaterial comprising an asbestos felt backing impregnated with anon-flammable elastomeric binder and a pigmented polyvinylfiuorideplastic. film se `cured to said backing by a thermosetting elastomericadhesive, said plastic lm being substantially opaque to protect theadhesive bond thereof to the backing from photochemic'ail degradation.

References Cited by the Examiner UNITED STATES PATENTS Harsh'berger etal 52-419 Smith 52-409 X Saunders 161-205 X Wilson 52--419l Almy et al161-205 X Simms 161-189 Usala et al 161-186 FOREIGN PATENTS 7/1959Canada.

OTHER REFERENCES 5 American Rooter and Building Improvement Contractor,TH'2431.A1.A5., October 1962, page 14.

Modern Plastics, TP98.6.A1M6, October 1959, pages 89-91, 200.

Modern Plastics, TP986.A1M6, September 1961, page 10 45.

FRANK L. ABBOTT, Primary Examiner.

' A. C. PERHAM, Assistant Examiner.

Disclaimer 3,300,927.-Phz`tlp Stephen Bettoti, Martinsville, NJ.LAMINATED SHEET MATERIAL. Patent dated Jan. 31, 1967. Disclaimer filedDec. 23, 1970, by the assignee, GAF Corporation. Hereby enters thisdisclaimer to claims 2 and 13 of said patent.

[/ft'ozal Gazette Febmafry 2, 1.971.]

11. A ROOF COMPRISING A ROOF DECK AND SUCCESSIVE LENGTHS OF FLEXIBLEROOFING MATERIAL HAVING A UNIFORM WIDTH, SAID MATERIAL COVERING SAIDROOF DECK, SAID ROOFING MATERIAL BEING WEATHER AND FIRE RESISTANT ANDUNIFORMLY SECURED TO SAID ROOF DECK WITH AN ASPHALTIC ADHESVIE, SAIDROOFING MATERIAL COMPRISING A PIGMENTED SUBSTANTIALLY OPAQUEPOLYVINYLFLUORIDE PLASTIC FILM HAVING A UNIFORM THICKNESS OF AT LEASTONE MIL, AND AN ASBESTOS FELT BACKING IMPREGNATED WITH FROM ABOUT 15% TOABOUT 25% BY WEIGHT OF POLYCHLOROPRENE, SAID FILM SECURED TO SAIDASBESTOS FELT BACKING BY MEANS OF A THERMOSETTING, ELASTOMERIC ADHESIVE,SAID ROOFING MATERIAL DISPOSED ION SAID ROOF DECK IN A MANNER SUCH THATA LONGITUDINAL EDGE OF ONE OF SAID LENGTHS OF ROOFING MATERIAL ABUTS THELONGITUDINAL EDGE OF ANOTHER OF SAID LENGTHS ADJACENT TO IT, THE SEAMDEFINED BY SAID ABUTTING LONGITUDINAL EDGES BEING SEALED BYPRESSURE-SENSITIVE ADHESIVE TAPE, SAID TAPE COMPRISING POLYVINYLFLUORIDEPLASTIC FILM.